Physics Software for the Macintosh

Spot graphs the spot diagrams of a newtonian telescope mirror. Programmed in Apple Computers Cocoa IDE using the C and Objective C languages.

Franklin

Electric Field Graphing Software

for Macintosh Computers only!

This program was inspired by
a program in John R. Merrill's

Using Computers In Physics.

Franklin produces nice 3D contour graphs of
equipotential surfaces and allows one to place point charges
in three dimensions. It is one of the few programs that treats
equipotential surfaces as truly 3 dimensional instead of 2 dimensional
closed curves. You can edit charges in a text window and save
them in a text file. The graphs are drawn in a fairly large window
(1000x800 pixels) and you may change the background and potential
colors to suit your taste. Although there are probably quite
a few electric field graphing programs around, I think the above
features make Franklin different from most. On the other hand
Franklin doesn't do some of the things common to these other
programs such as drawing field strength vectors and automatically
spacing field lines around the charges. These things aren't very
important to me but if they are to you, one of these other programs
may be more useful. I think Franklin would still be a good compliment
to one of these other programs however.

None of these point charge graphing programs,
including Franklin, are very useful for most real world electrostatic
problems. One reason is that most real world problems involve
continuous materials instead of point charges. But a more important
reason is that most problems involve the application of voltages
to boundary surfaces. These boundary conditions then guarantee
a unique potential everywhere else. On a conductor the charges
arrange themselves in a manner that produces the given boundary
condition there.The actual arrangement of these charges isn't
important in solving Laplaces equation outside the conductors,
only the boundary conditions are needed. Except for the method
of images I don't see how this sort of problem can translate
well to a point charge graphing program.